The tip about turning off GPS is wrong and will not save battery. Android is extremely efficient about using GPS, and automatically turns the GPS on and off.
You can help your batterty life by choosing "Network Location" instead of "GPS Location" in applications that do not require pinpoint accuracy (like weather apps, serach portal apps, etc.). That way only location-critical apps, like Maps or Navigation, will ever turn on the GPS radio. And they will do so only when needed.
But the tip about turning off GPS -- complete wrong.